The microblog: 2018.03.23 18:05:13

2018.03.23 18:05:13 (977229793476399105) from Daniel J. Bernstein, replying to "Jonathan Oppenheim (@postquantum)" (977081987163938816):

A black hole is a very strong potential well. Your naive belief that this hides information is wrong: see Hawking radiation, horizon fluctuatons, etc. The holographic principle says that all information in a volume of space is encoded on a faraway boundary.

2018.03.23 18:10:15 (977231061804634112) from Daniel J. Bernstein:

If you naively think you can hide inside a black hole (or a less extreme potential well) and roll quantum dice to fill up the space around you with new random numbers hidden from the outside, you're wrong. See Bekenstein's entropy bound.

2018.03.23 18:18:05 (977233031667830786) from Daniel J. Bernstein:

QKD proponents claim that the security of QKD is guaranteed by the laws of physics. What we see throughout this Twitter thread is proponents switching to weaker claims (yes, there's leakage, but _hopefully_ hard to invert) without admitting that the original claim is bullshit.

2018.03.23 18:29:50 (977235989344260096) from Daniel J. Bernstein:

Examples of leakage already admitted in this thread: femtosecond transients; X-rays; neutrinos; gravitational waves. And then there are the corpses of "secure" QKD systems broken by Makarov et al., and the holographic principle giving a theoretical framework for QKD breakability.

2018.03.23 18:38:42 (977238218356781056) from Daniel J. Bernstein:

Even when QKD proponents admit that they're switching from zero-interaction claims to (hopefully-)small-interaction claims, they go back to putting the unjustifiable zero-interaction bullshit into their followup papers and grant proposals.


2018.03.23 00:30:38 (976964397104074752) from Daniel J. Bernstein, replying to "Frédéric Grosshans (@fgrosshans)" (976960495025565696):

The paper goes far beyond your characterization, as illustrated by, e.g., the paper's analysis of "the widespread misconception that the shielding is exponential" in the gap size etc.

2018.03.23 01:53:06 (976985150469935104) from "Frédéric Grosshans (@fgrosshans)":

The paper itself says "This Helmholtz equation model is highly simplified", and it indeed raises the valid point that a cage should be modelled properly, specially concerning the gaps (I actually shared the misconception Before reading the paper)

2018.03.23 02:28:44 (976994119406014465) from Daniel J. Bernstein, replying to "Frédéric Grosshans (@fgrosshans)" (976985150469935104):

And you claim that these issues disappear when the gaps are atomic-scale? Where can I find a theorem that derives your claimed QKD non-leakage from the laws of physics without _assuming_ non-leakage? And how do you explain the evident contradiction with the holographic principle?

2018.03.23 08:17:53 (977081987163938816) from "Jonathan Oppenheim (@postquantum)":

The holographic conjecture just claims that two different theories (one in lower dimension) are equivalent. How does that imply that it is impossible to localise information? And will you now reveal what law of nature forbids the lab from being located in a deep potential well?